•A surface spillway were found to has a region to be potentially detrimental to fish.•The Surface Spillway was modified accordingly and its efficacy was evaluated.•The modifications resulted in ...improved hydraulic and fish passage conditions.•Results provide critical insight for design and evaluation of fish-friendly spillways.
Spillway passage is one of the commonly accepted dam passage alternatives for downstream-migrating salmonids and other species. Fish passing in spill near the water surface may have improved chances of survival over fish that pass deeper in the water column near spillway structures. In this study, an autonomous sensor device (Sensor Fish) was deployed in 2005 to evaluate fish passage conditions through the Removable Spillway Weir (RSW) at Ice Harbor Dam on the Snake River in south-central Washington State. The Sensor Fish deployment was undertaken concurrently with a separate live fish injury and survival study. Conditions at the RSW–Spillway Chute Transition and Deflector region were found to be potentially detrimental to fish. As a result, the spillway slope and deflector radius were modified, and the efficacy of the modifications was evaluated in 2015 using Sensor Fish and a concurrent live fish study. The frequency of severe acceleration events (acceleration≥95G) during passage decreased significantly (from 51% to 35%; p-value=0.049), and collisions with structures decreased from 47% to 27% (p-value=0.015). Pressures observed in the Spillway–Deflector region and pressure rates of change decreased as well. Overall, the modifications resulted in hydraulic conditions that contributed to improved fish passage conditions and increased fish survival.
► Mechanisms of tDCS enhancement of hidden object detection was examined. ► Target object detection accuracy and d′ were increased by tDCS. ► Response bias β was not affected by tDCS. ► Effects were ...largest for repeated images that contained hidden objects. ► Single-blind and double-blind task designs produced similar results.
We have previously found that transcranial direct current stimulation (tDCS) over right inferior frontal cortex (RIFC) enhances performance during learning of a difficult visual target detection task (Clark et al., 2012). In order to examine the cognitive mechanisms of tDCS that lead to enhanced performance, here we analyzed its differential effects on responses to stimuli that varied by repetition and target presence, differences related to expectancy by comparing performance in single- and double-blind task designs, and individual differences in skin stimulation and mood. Participants were trained for 1h to detect target objects hidden in a complex virtual environment, while anodal tDCS was applied over RIFC at 0.1mA or 2.0mA for the first 30min. Participants were tested immediately before and after training and again 1h later. Higher tDCS current was associated with increased performance for all test stimuli, but was greatest for repeated test stimuli with the presence of hidden-targets. This finding was replicated in a second set of subjects using a double-blind task design. Accuracy for target detection discrimination sensitivity (d′; Z(hits)−Z(false alarms)) was greater for 2.0mA current (1.77) compared with 0.1mA (0.95), with no differences in response bias (β). Taken together, these findings indicate that the enhancement of performance with tDCS is sensitive to stimulus repetition and target presence, but not to changes in expectancy, mood, or type of blinded task design. The implications of these findings for understanding the cognitive mechanisms of tDCS are discussed.
One of the most cost-effective and environmentally sound methods of developing hydropower is through the uprating of hydroelectric turbines. In many countries hydroelectric dams have turbines that ...are approaching their expected service life, with plans underway to install replacement turbines that are expected to improve fish passage survival. To validate these improvements, there is a need to develop a baseline hydraulic characterization of existing Kaplan turbines. An autonomous sensor device known as the Sensor Fish was deployed at Ice Harbor Dam to characterize the hydraulics under different operating conditions. Nadir pressures varied by operating condition, with values decreasing with operating power (144–106 kPaA). Pressure changes during turbine passage varied by operating condition, with values increasing with operating power (311–344 kPa). There were slightly more significant events (acceleration ≥95G) in the stay vane/wicket gate region than the runner region. Rotational velocity data were similar between operating conditions. Sensor Fish data amassed during field studies in similar turbines were used for comparison. This study offers critical insights into the biological performance of large Kaplan turbines and provides vital information that can be used to make informed decisions that lead to additional design or operational improvements.
•Sensor Fish data collected in a large Kaplan turbine at Ice Harbor Dam.•Nadir pressure and rotational velocity were lowest among turbines compared.•Severe acceleration events were similar among the turbines compared.•Data provides insight into the biological performance of large Kaplan turbines.•Data provides information that can lead to further design/operational improvements.
The Juvenile Salmon Acoustic Telemetry System, developed by the U.S. Army Corps of Engineers, Portland District, has been used to monitor the survival of juvenile salmonids passing through ...hydroelectric facilities in the Federal Columbia River Power System. Cabled hydrophone arrays deployed at dams receive coded transmissions sent from acoustic transmitters implanted in fish. The signals' time of arrival on different hydrophones is used to track fish in 3D. In this article, a new algorithm that decodes the received transmissions is described and the results are compared to results for the previous decoding algorithm. In a laboratory environment, the new decoder was able to decode signals with lower signal strength than the previous decoder, effectively increasing decoding efficiency and range. In field testing, the new algorithm decoded significantly more signals than the previous decoder and three-dimensional tracking experiments showed that the new decoder's time-of-arrival estimates were accurate. At multiple distances from hydrophones, the new algorithm tracked more points more accurately than the previous decoder. The new algorithm was also more than 10 times faster, which is critical for real-time applications on an embedded system.
BladeCenter packaging, power, and cooling Crippen, M. J.; Alo, R. K.; Champion, D. ...
IBM journal of research and development,
11/2005, Volume:
49, Issue:
6
Journal Article
Peer reviewed
This paper addresses the packaging, power, and cooling of the IBM eServer(TM) BladeCenter® compact server infrastructure consisting of 14 servers in a 7 U (1U = 44.45 mm) vertical space for ...installation in an industry-standard rack. A typical rack is 42U tall. Therefore, six BladeCenter systems will fit in a rack, for a total of 84 servers. The density of a BladeCenter system (servers/ U) is double that of previous 1U rack-optimized servers. To build such a dense server system required overcoming a multitude of challenges in packaging, power, and cooling design. Our approach to these challenges is described, but in the broader context of not only increasing the density, but setting a new server standard for a highly available redundant infrastructure with integrated systems management and network switching that uses less power and is simple to maintain on site or remotely, even by nonspecialized personnel. Server processors, memory, storage, and input/output devices were combined in a single compact server unit called a processor blade, while the support infrastructure, such as systems management, network connectivity, optical media, power, and cooling, was consolidated in a single structure and shared among many servers. The result is a package architecture that lends itself well to standardization. Custom server blades and input/output devices may be designed in accordance with BladeCenter base specifications and be effectively integrated into the blade server system. PUBLICATION ABSTRACT
Fish passing downstream through hydroelectric facilities may pass through turbines where they experience a rapid decrease in pressure, which can lead to barotraumas including swim bladder rupture, ...exopthalmia, emboli, and hemorrhaging. In juvenile Chinook salmon, the main mechanism for injury is thought to be expansion of existing gases (particularly those present in the swim bladder) and the rupture of the swim bladder ultimately leading to exopthalmia, emboli and hemorrhaging. In fish lacking a swim bladder, such as lamprey, barotraumas due to rapid decompression may be reduced, however this has yet to be extensively studied. Another mechanism for barotrauma can be gases coming out of solution and the rate of this occurrence may vary among species. In this study, juvenile brook and Pacific lamprey acclimated to 146.2kPa (equivalent to a depth of 4.6m) were subjected to rapid (<1s) or sustained decompression (17min) to a very low pressure (13.8kPa) using a protocol previously applied to juvenile salmon. No mortality or evidence of barotraumas was observed following rapid decompression, nor up to 120h after sustained decompression. In contrast, mortality or injury would be expected for 97.5% of juvenile Chinook salmon exposed to a similar rapid decompression to these very low pressures. Additionally, juvenile Chinook salmon experiencing sustained decompression died within 7min. Thus, juvenile lamprey may not be susceptible to barotraumas associated with turbine passage to the same degree as juvenile salmonids.
Previous studies have found a benefit of closed-loop transcranial alternating current stimulation (CL-tACS) matched to ongoing slow-wave oscillations (SWO) during sleep on memory consolidation for ...words in a paired associates task (PAT). Here, we examined the effects of CL-tACS in a retroactive interference PAT (ri-PAT) paradigm, where additional stimuli were presented to increase interference and reduce memory performance. Thirty-one participants were tested on a PAT before sleep, and CL-tACS was applied over the right and left DLPFC (F3 and F4) vs. mastoids for five cycles after detection of the onset of each discrete event of SWO during sleep. Participants were awoken the following morning, learned a new PAT list, and then were tested on the original list. There was a significant effect of stimulation condition (
= 0.04297; Cohen's
= 0.768), where verum stimulation resulted in reduced retroactive interference compared with sham and a significant interaction of encoding strength and stimulation condition (
= 0.03591). Planned simple effects testing within levels of encoding revealed a significant effect of stimulation only for low-encoders (
= 0.0066; Cohen's
= 1.075) but not high-encoders. We demonstrate here for the first time that CL-tACS during sleep can enhance the protective benefits on retroactive interference in participants who have lower encoding aptitude.
Microbial volatiles provide essential information for animals, which compete to detect, respond to, and perhaps control this information. Burying beetle parents have the opportunity to influence ...microbially derived semiochemicals, because they monopolize a small carcass for their family, repairing feeding holes and applying exudates that alter the microbial community. To study adaptive manipulation of microbial cues, we integrated mechanistic and functional approaches. We contrasted gas chromatography–mass spectrometry (GC-MS) volatile profiles from carcasses that were or were not prepared by a resident pair of Nicrophorus orbicollis. Methyl thiocyanate (MeSCN), the primary attractant for burying beetles seeking a fresh carcass, was reduced 20-fold by carcass preparation, while dimethyl trisulfide (DMTS), which deters breeding beetles, was increased 20-fold. These results suggest that parental care serves to make previously public information more private (crypsis, MeSCN) and to disinform rivals with a deterrent (DMTS). Functional tests in the field demonstrated that carcass preparation reduced discovery and use by congeners (threefold) as well as by dipteran rivals. Because microbes and their chemicals influence nearly every aspect of animal ecology, animal manipulation of microbial cues may be as widespread as manipulation of their own signals.
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